Plan eligibility error - is this eligible for correction through the SCP under Revenue Procedure 2021-30?

Good afternoon,

CPA here auditing a plan and hoping to run by an error encountered in the first-ever audit of a 401(k) plan. Facts are as follows:

• From inception 1/1/2019 through 12/31/20, the effective plan document had a 1 year service requirement with monthly entry and an autoenrollment feature. During this period, the plan operated as if the eligibility was immediate upon hire. 
• Effective 1/1/21, the plan was restated to change the eligibility/entry date provisions to immediate and removed the autoenrollment feature.

My question is: Can the plan sponsor correct the error related to the 2019 and 2020 plan years through the SCP under Revenue Procedure 2021-30 by retroactively amending the plan's service and entry date requirements to immediate to conform to how the plan operated during 2019 and 2020? 

Based on my reading if the Rev Proc, I would think the answer is yes as the amendment resulted in "an increase of a benefit, right, or feature", but am wondering if I am missing something?

Thank you!

Yes, the eligibility requirements in this case may be retroactively corrected by amendment under SCP.